Vala Panel Application Menu is a Global Menu applet for use with 
Vala Panel, xfce4-panel and mate-panel (Budgie 10.x is also planned).

By default vala-panel-appmenu will be builded for xfce-panel.
Requires bamf must be built without   --disable-introspection
Optionaly requires appmenu-qt

For XFCE-Panel, type the following lines into your console: 
xfconf-query -c xsettings -p /Gtk/ShellShowsMenubar -n -t bool -s true 
xfconf-query -c xsettings -p /Gtk/ShellShowsAppmenu -n -t bool -s true